import java.sql.*;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {

        class Hello {
            //psvm
            public static void main(String[] args) {
                //jdbc 步骤
                // 1.加载驱动
                try {
                    Class.forName("com.mysql.cj.jdbc.Driver");
                    //2.创建链接
                    String url = "jdbc:mysql://localhost:3306/test";
                    Connection connection = DriverManager.getConnection(url, "root", "");
                    if (connection != null) {
                        System.out.println("成功");
                    }
                    // 3.写sql
                    String sql = "select * from user3";
                    // 4.预编译sql
                    PreparedStatement preparedStatement = connection.prepareStatement(sql);

                    //5.执行sql
                    ResultSet resultSet = preparedStatement.executeQuery(sql);
                    //6.遍历结果
                    while (resultSet.next()) {
                        int id = resultSet.getInt(1);
                        String name = resultSet.getString(2);
                        String pass = resultSet.getString(3);
                        System.out.println(id + " " + name + " " + pass);
                    }
                    //7.关闭资源（谁最后创建的谁最先关闭）
                    resultSet.close();
                    preparedStatement.close();
                    connection.close();


                } catch (ClassNotFoundException | SQLException e) {
                    throw new RuntimeException(e);
                } finally {
                    //关闭资源的代码放在这第七步里更合理，但若放在这里，需扩大try的范围。
                }

            }

        }
    }
}

